mirror of
https://github.com/idris-lang/Idris2.git
synced 2024-12-19 01:01:59 +03:00
59 lines
1.4 KiB
Idris
59 lines
1.4 KiB
Idris
module Data.These
|
|
|
|
%default total
|
|
|
|
public export
|
|
data These a b = This a | That b | Both a b
|
|
|
|
public export
|
|
fromEither : Either a b -> These a b
|
|
fromEither = either This That
|
|
|
|
public export
|
|
fromThis : These a b -> Maybe a
|
|
fromThis (This a) = Just a
|
|
fromThis (That _) = Nothing
|
|
fromThis (Both a _) = Just a
|
|
|
|
public export
|
|
fromThat : These a b -> Maybe b
|
|
fromThat (This _) = Nothing
|
|
fromThat (That b) = Just b
|
|
fromThat (Both _ b) = Just b
|
|
|
|
public export
|
|
these : (a -> c) -> (b -> c) -> (a -> b -> c) -> These a b -> c
|
|
these l r lr (This a) = l a
|
|
these l r lr (That b) = r b
|
|
these l r lr (Both a b) = lr a b
|
|
|
|
public export
|
|
(Show a, Show b) => Show (These a b) where
|
|
showPrec d (This x) = showCon d "This" $ showArg x
|
|
showPrec d (That x) = showCon d "That" $ showArg x
|
|
showPrec d (Both x y) = showCon d "Both" $ showArg x ++ showArg y
|
|
|
|
%inline
|
|
public export
|
|
Bifunctor These where
|
|
bimap f g (This a) = This (f a)
|
|
bimap f g (That b) = That (g b)
|
|
bimap f g (Both a b) = Both (f a) (g b)
|
|
|
|
%inline
|
|
public export
|
|
Functor (These a) where
|
|
map = mapSnd
|
|
|
|
public export
|
|
bifold : Monoid m => These m m -> m
|
|
bifold (This a) = a
|
|
bifold (That b) = b
|
|
bifold (Both a b) = a <+> b
|
|
|
|
public export
|
|
bitraverse : Applicative f => (a -> f c) -> (b -> f d) -> These a b -> f (These c d)
|
|
bitraverse f g (This a) = [| This (f a) |]
|
|
bitraverse f g (That b) = [| That (g b) |]
|
|
bitraverse f g (Both a b) = [| Both (f a) (g b) |]
|